Inorganic plastic cement such as magnesium oxychloride and magnesium oxysulfate cements have been described in numerous patents. Cements of this type are highly desirable if they can be uniformly produced and molded since parts made from such materials possess excellent fire retardant properties. When reinforced with glass fibers to provide suitable strength, molded oxychloride or oxysulfate cements may be used to produce articles such as boat parts, building panels and the like for use in high fire risk areas. The mixing of the materials that form the oxychloride and oxysulfate compositions often involve the use of prolonged mixing cycles or high shear blending techniques. These procedures are described in U.S. Pat. Nos. 3,320,077 and 2,939,799.
During the mixing of the ingredients magnesium oxide with the magnesium chloride and/or magnesium sulfate solutions used to prepare the oxycements, excessive temperature conditions occurring in the mixing equipment can result in a premature setting of the oxychloride cement causing the mixing zone to be fouled with a cement that is already set up. Further, it is often necessary to conduct a mixing operation in externally cooled mixing equipment that adds considerably to the cost of the product. Thus, the controlling of the mixing of the inorganic cement ingredients to minimize these problems is desirable provided satisfactory cements can be produced while remedying the aforementioned problem.